scholarly journals Added resistance, heave and pitch for the KVLCC2 tanker using a fully nonlinear unsteady potential flow boundary element method

2021 ◽  
Vol 229 ◽  
pp. 108935
Author(s):  
Francesco Coslovich ◽  
Martin Kjellberg ◽  
Magnus Östberg ◽  
Carl-Erik Janson
2015 ◽  
Author(s):  
W. James Doyle ◽  
Lauren S. Schambach ◽  
Marc V. Smith ◽  
Charles Field ◽  
Christopher J. Hart

Aegir is a medium-fidelity potential flow code that uses a high-order, non-uniform rational B-Spline (NURBS) based boundary-element method for the computation of steady and unsteady ship hydrodynamics. This paper documents verification and validation for Aegir in its steady-state wave resistance prediction mode and Aegir’s LEAPS to Aegir function. A set of best practice guidelines has been created to aid the user in selecting initial input parameters, which reduces the necessary time for verification. This paper also presents validation of the numerical solution versus physical experiments from publically available ship data sets. Aegir has become more prevalent in the naval ship design community and is now a part of the US Navy’s Integrated Hydrodynamic Design Environment (IHDE).


2014 ◽  
Vol 644-650 ◽  
pp. 628-631
Author(s):  
Ke Yi Li ◽  
Zhong Cai Pei

When the bubble moves in the vicinity of a free surface, the movement will be affected by the buoyancy and the Bjerknes effect. Blake and Gibson proposed the criterion which determined the motion direction of the jet and the dynamics of bubble. They proposed the jet wouldn’t be formed in the condition that . Based on the potential flow theory, boundary element method (BEM) is used to calculate three typical examples in this paper in order to study the dynamics of the bubble under the combined action of the Bjerknes effect of the free surface and the buoyancy. It is found out during the analysis that the Blake criterion is applicable to predict the conditions that and .


2008 ◽  
Vol 15 (1) ◽  
pp. 33-50 ◽  
Author(s):  
Ho-Won Lee ◽  
Suk-Yoon Hong ◽  
Do-Hyun Park ◽  
Hyun-Wung Kwon

In this paper, Energy Flow Boundary Element Method (EFBEM) was developed to predict the vibration behavior of one- and two-dimensional structures in the medium-to-high frequency ranges. Free Space Green functions used in the method were obtained from EFA energy equations. Direct and indirect EFBEMs were formulated for both one- and two-dimensional cases, and numerically applied to predict the energy density and intensity distributions of simple Euler-Bernoulli beams, single rectangular thin plates, and L-shaped thin plates vibrating in the medium-to-high frequency ranges. The results from these methods were compared with the EFA solutions to verify the EFBEM.


Author(s):  
Caroline H. Hague ◽  
Chris Swan

This paper concerns the description of extreme surface water waves in deep water. A fully nonlinear numerical wave model in three dimensions is presented, based on the Boundary Element Method (BEM), and is applied to nonlinear focusing of wave components with varying frequency and direction of propagation to form highly nonlinear groups. By using multiple fluxes at corners and edges of the numerical domain the “corner problem” associated with BEM-based models in physical space is overcome. A two-dimensional version of the method is also employed to model unidirectional cases, and examples presented include the focusing of Top Hat spectra in deep water to form highly nonlinear wave groups at or close to their breaking limit. The ability of the model to accurately simulate these sea states is highlighted by comparison to the fully nonlinear model of Bateman, Swan and Taylor (2001, 2003).


Author(s):  
Chengxi Li ◽  
Yuming Liu

The objective of this work is to understand and evaluate the hydrodynamics modeling of a floating rigid body in regular and irregular ocean surface waves. Direct time-domain numerical simulation, based on the potential-flow formulation with the use of a quadratic boundary element method, is employed to compute the response of the body under the action of surface waves including fully-nonlinear wave-body interaction effects associated with steep waves and large-amplitude body motions. The viscous effect due to flow separation and turbulence is included by empirical modeling. The simulation results of body motions are compared with laboratory experimental measurements. The nonlinear effects due to body motion and wave motion are quantified and compared to the viscous effect. Their relative importance in the prediction and modeling of a rigid body motion under various wave conditions is investigated. This study may provide essential information pertaining to develop effective modeling of nonlinear wave-body interactions which is needed in design of offshore structures and wave energy conversion devices.


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